1. Field of the Invention
The present invention relates to a chronograph timepiece having a time indicating function and a time measuring function.
2. Description of the Related Art
Conventionally, there has been developed a chronograph timepiece in which a plurality of drive motors are mounted in order to individually drive a plurality of indicator hands and which is endowed with a time indicating function as a basic function and, further, a chronograph measuring function for performing time measurement, wherein the driving of the indicator hands is electrically effected by the drive motors, and the zero-restoring of the chronograph hands is effected by a mechanical mechanism such as hearts (See, for example, JP-A-2005-3493 and JP-A-61-73085 regarding the chronograph timepiece, and JP-A-2003-185765 regarding the motors).
For example, in the chronograph timepiece as disclosed in JP-A-61-73085, when a reset button is depressed during chronograph measuring operation (FIG. 11), a contact portion 305 is placed in a contact state, and a hammer 128 rotates a hammer operating lever 280, effecting the zero-restoring of the chronograph hands by hearts 281 and 291. In the case in which drive pulses for chronograph hand drive are being output when the contact point 305 is placed in a contact state and a chronograph reset signal is input, the timing of the setting by the hearts and the timing of the drive pulses overlap each other to thereby place a stepping motor in a non-rotation state. Even if rotation detection is effected to detect the non-rotation, a correction drive pulse is allowed to be output immediately thereafter. As a result, solely the polarity of the drive pulses stored in an integrated circuit (IC) is reversed, with the chronograph motor not rotating; thus, when chronograph measurement is restarted, the stepping motor does not rotate at the time of the first drive.
On the other hand, JP-A-2006-90769 discloses a chronograph timepiece equipped with a mechanical safety mechanism which prevents resetting from being effected even if resetting operation is performed during chronograph operation; in the above-mentioned chronograph timepiece, however, the mechanical mechanism is rather complicated, and a high cost is involved.
JP-A-2003-4872 and JP-A-59-20885 disclose inventions according to which hand movement is stopped through detection of rotation. JP-A-2003-4872 discloses an analog electronic timepiece in which hand movement is stopped when the result of the detection of rotation at the time of correction drive is non-rotation. In order to prevent abnormal wear and breakage, when the result of the detection of rotation after normal hand movement pulse drive is non-rotation, correction drive pulse drive is conducted, and the hand movement is stopped when the result of the detection of rotation effected again is non-rotation. Further, JP-A-59-20885 discloses an electronic timepiece which is equipped with a second hand drive motor and an hour/minute drive motor, wherein, in order to inform the user of any abnormality, when non-rotation of the rotor of the hour/minute drive motor is detected, the driving of the second hand drive motor is stopped. None of the above-mentioned inventions helps to solve the problem of non-rotation at the time of restarting.